Polythiaalkylacrylates



. Richard M. M cCurdy, St. Paul, and Julianne H. Prager,

Roseville, Minn'., assiglrors'to Minnesota Mining and Manufacturing Company, St. Paul, Minn.',' a 'corporato parafiinic solventsL Another object 7 r ,is to produce usefulpollyi t f risiwhiclif are; resistant-to ward mercaptans." A still further-object of the,iriv'e'r'i't'ionf;-

to provide monomersfaiidlowfpolymers'which are suitable for I copolymerization with other pdlyr'neriiable the conditions of extremely low-teniperatures' dffen vailin'gathighaltitudes,'whileresistance tosolv ts's I as hydrocarbon fuels is-neces'sar'y'. The less ture and ready accessibilit'y'of the novel elastonieifsfof United statespatfifol r 2,925,406 i POLYTHIAALKYLACRYLATES tion of Delaware No Drawing. Application April 8, 1957 1 Serial No. 651,164 1 8 Claims. cl. 250- 795 This invention relates to a novel class ofuseful polymers' and more particularly to certain polythiaalkyl acrylates. t

The polymers coming within the scope of the invention are typified by the presence of r'ecurringiunits which can be represented by the formula wherein R and R are linear hydrocarbon residues, R

' The'physical'properties ofitheipolymers are dependent upon their molecular weightfldwer inernbe being-viscous liquids while polymersfof'high*averag molecular weightare'solid elastomersi';

It isfan'object of this;invention-.to'pro 1 substances.

Other obj ects of" the" invention" will 'bje"ap parent from the disclosure hereinafter'setforth;

In accordance with these objects it has been found? that higher polymers of the present invention" are easily and relatively cheaply prepared elastomer's which have outstanding resistance to paraffinic hydrocarbon solvents, over a wide range of temperatures; Thus they havedistince advantagessince elastomersfpossessing"these properties, find specific applications in military and: civilian aircraft in sealing joints, hoses, connections and'rthefll ilte where pressure resistance and el'asticity are'requir ed under ostly the invention permits the liberal applicatio standingniaterials ln'instan'c'es'where addi onal safety may warrant employing a superior"'producf'but cannotq justify use of a'-very"expensive productf that similar and other uses fare"possible-inthe'fatitriib 1r: evident tive industry. The polymers of the present invention, further lend themselves well to formulation of pressurese'nsit ive adhesives having resistanceto parafiiriic oils;

They further combine with th'eir' desirable lew-tem erature properties and resistance to hydrocarbons, resistance t6 mercaptans of-the type found-in sonr=emde or11na1je i'ng them -ofv-aluefor applications where'- expdsiire o wells. and refineries, in pumpparts, I paclgi'n oftthe series a nothave af'tend ency to atta ek' iron or ather susceptible metals under these conditions. a

In the measure me nt of propertiesof elastomeric poly temperature, symbolized T sometimes called glass transition temperature (of. P. T. Flory, Principles of 10 Polymer Chemistry, Cornell University. Press, 1953 The method employed herein'for measuring this value is that described in the Journal .of- PolymertScie nce volume 3', pages 455 to 461tand '64? to 65.11. i The resistance of thefelast'omers to solvents is measured herein by a standand method,ASTM Procedure 131471-541 At temperatures below the glassi 'temperature. an elastomeric polymer becomes more or less. frangible, which is highly undesirable for'many.purposes. Alow value of T iis therefore" evidence of-utility at comparably low tempera- '20 tur'esl For'maxi'mum utilityfor the purposes described L.glassj' temperature, this l'has heretofore generally been I I accomplished atthe enpense ofsresistance to; solvents and .bemgmonovalent and Rt'r d1va1ent,and-the sumtof the a ;c arbon,atoms of R and-Ris from 3 to'7.

r si s 1e w h. eavim'q a'i sm e aot m .r iz 2 9 s tt a e lytu atur ss m nema 19 since. thenvthe above described advantages f 9?}??? liq pe piyiii ts l-t iagp es ntii ent n; e ncorporated substantially proportionally into the; resulting copolymers and -in; addition some "internal plasticization V 5 is: effected. As eggarnples of such 'cornonomers suitable V Mid rsi ilme b mept natvin a p dev s yr m Y- and h l a ate rae lic; acid, m y

- ethylmethacrylates, N-vinyl;pyridine and;thelike, 7

' The polymers of the inventionare obtained by poly-t ,merization of acrylateesters of thiaalkanols. The 'acryl-ateester monomers' are conveniently prepared byreacting the selected thiaalkanol iwith acrylic acid or with a sligh t excess of acrylylchloride in inert solvent solution,

and intthe presence of "a basic material, for example, such asaslight stoichiometrio excess of anhydrous triethylamine; Theifollowing. equatiomin which Rand K have h l i8i fi=sPPT $i h t t rth: h t aa svmerve to illustrate' the. course: of the reaction where acrylic ac id tThemthiaalkanolst usedtaststartingmaterials .can.be pre pared; by the reaction1 oftsodiotderivatives of mercaptans ico ntaining menswear, withjthe selected chloroalkanol containiii'"'tlieK "radiEa1,wlfefein li'and li" have-tile significan e defined hereinabove.

1;'Impsgage niaalkynei me esters of the invention are, forexample, 3- thiabutyl acrylate, B-thiaheXyl ,acrylate, 6-t

late and 4-th1apentyl acrylate."

mere by: any of persulfuric acid, p'e roxides, diazoinitiators andithe like.

I" iq,n oducetpo yme stq ower aver g .moleculartweight,

including-liquid polymers,-,;mercaptan or other chain T transfer agents are employed?" Preferably, theyare poly-j M 12 ,ts za darpr esses- :Th

t lbvt m lsiqnr .z s tablei s'tisea u ti iq asts ah .L p F 35% solids, can be used as such, for incorporation into paints, paper treatment and the like; but preferably the elastomer is isolated and compounded with fillers, vulcanizing agents and-the like to produce rubber having useful properties in applications such as gaskets, seal rings and the like. e

The following examples, which are included for illustrative purposes, and which. do not limit the scope of the invention, will more specifically describe the preparation and properties of the monomers and polymers of the invention. In the examples, all parts are by weight unless otherwise specified.

EXAMPLE 1 In a vessel equipped with mechanical stirrer, thermometer and reflux condenser, 100 parts of ethanethiol were neutralized by the careful addition of 290 parts of 25% sodium hydroxide solution at such a rate that the.

' temperature did not exceed 20 C. To the resulting clear solution were then added 145 parts of ethylene chlorohydrin at a rate such that the temperature did not exceed 60 C. Stirring was continued for one hour, after which the organic layer was taken up in 150 ml. of benzene, washed successively with 15% sodium hydroxide solution and water, the solution dried over anhydrous calcium sulfate and fractionally distilled under reduced pressure. The 3-thiapentanol-1 thus prepared boiled at 67/7 mm.

To an ice cold' solution of 248 parts of 3-thiapentanol-1 and 259 parts of anhydrous triethylamine in 900 parts of 1 benzene in a vessel equipped with stirrervand thermometer was added gradually a solutionof 222 parts of acrylyl chloride in 400 parts of benzene. The temperatureof the reaction mixture was maintained at 15 C. by coolingthe vessel in an ice bath." The reaction mixture was filtered,

washed with dilute hydrochloric acid and water, dried, and'distilled. The resulting 3-thiapentyl acrylate boiled Tat 62 c./o.s mm. 1

Using substantially the above described procedure and sequence of reactions, other thiaalkanols and their acrylates were prepared. These were'characterized by boiling points, refractive indices and analytical results as shown in the following tables 7 Table I. Thiaalkan0ls Analysis B.P., m

C H S 3-tl1iabutanoI-1 74-8/23 1.4891 Calculated 39.1 8.8 34. 2 mm. Found 38.2 9.1 34. Mshiapentanol-L. 78-81/21 1.4841 Calculated 45.2 9.5. 30. mm. Found 45.1 9. 5 29. 4-thiapentanol-L. 52-5/1.5 1.4859 Calculated.- 45.2 9.5 30. mm. Found 45.4 9.5 30. 4-thiahexanol-1 85-6/5 1.4830 Calculated 50.0 10.1 26. mm. Found 49.8' ,9.8 26. 5-thiahexau0l-1. 81-5/3 1.4856 Galculated 50.0 10;1 26. mm. Found. 49.2 10.0 26.

Table II.-Thzaalkyl acrylates Analysis B.P., n

O H S 3-thiabutyl 60/4 mm- 1.4790 Calculated" 49.3 6.9 21. acrylate. Found 49.5 6.8 21. 3-thiapcutyl 83-5/7mm- 1.4763 Calculated" 52.5 7.6 20. acrylate. Found 52.6 7.5 20. 4-thiapentyl 52-5/1.3 1.4778 Calculated" 52.5 7.6 20. acrylate. mm. Found 52.7 7.6 20. 4-thiahexyl 578, 0.5: 1.4770 Calculated" 55.1 8.1 18. acrylate. 63-5/3 Found 55.1 7.9 18.

mm. S-thiahexyl 815/31nm 1.4856 Calculated 55.1 8.1 18

acrylate. Found 55.2 8.0 18.

EXAMPLE 2.

ooqm n-neutewon A mixture of 100 parts of B-thiapentyl acrylate, 180 v V parts of water, -5 parts of sodium lauryl sulfate and 0.5 -porating the respective ingredients into the elast'om'er'in parts each of sodium persulfate and sodium-bisulfite was placed in a suitable reaction vessel. The air in the vessel was then displaced by nitrogen, suitably by flushing with a stream of nitrogen for at least 2 minutes, and the vessel was sealed in a nitrogen atmosphere and transferred to a water bath at about 50 C. in which it was agitated by shaking for about 3 hours. The polymer which was formed was a pale bluish latex, from which the solid polymer was recovered by coagulation in about two volumes of methanol. The precipitated polymer was Washed with water and dried. It was a rubbery, virtually colorless mass. This polymer is comprised of recurring units having the formula TABLE III Volume per- Glass Tempcent swell Monomer employed perature I a 0.) isooctanetoluene ,60 9 '71 .31 65 82 -76 36 5-thiahexyl ucrylate 70 36 3 oxabutyl aorylate 50 30 3-oxapentyl acrylate... 50' --50 4-oxahexyl acrylate. u 68 130 n-butyl acrylate..-" 70 n-pentyl acrylate 76 200 From the tabulated results it is seen that the polymers of the present invention have much better solvent resistance than similar polyalkylacrylates, which are swollen to the extent of over 100% by the solvent mixture employed. The polythiaalkyl-acrylates of this invention have significantly better glassv temperatures than the polyoxaalkyl acrylates. It is in fact surprising. that although replacement of a methylene group by an oxa group raises the glass temperature, introduction of the even larger t hia' group results in lowering of the glass temperatures and marked improvement in solvent resistance. The class of polymers of the present invention consequently is a group possessing an unusual and unpredictable combine tion of properties of low glass temperatures and excellent solventresistance.

. The thiaalkyl acrylate polymers of the present invention are readily vulcanizable to compounded rubbers v possessing unusually good physical properties, as shown the following example. 1

EXAMPLE 3 A mixture of the following ingredients in which parts Di-Cup. 40/ C (40% commercial dicumyl peroxide) The mixture was compounded by successively incora cold rubber mill. The'compounded.stockiwas then 1 vulcanized in steel molds at 310 F. for 30 minutes under pressure to give a sheet about 0.1 inch thick. A sample was cut from the sheet in a dumbbell shape and'was then clamped in the jaws of an elongation testing device and stretched. A pull of 854 p.s.i. of minimum initial crosssection was required for 100% elongation and they sample broke at 1240 p.s.i. at which point' it had elongated 150%. There was a 12.5% deformation at this point indicating an amount of non-elastic stretching.

Portions of this same material were tested to determine the temperature of brittleness (T and the temperature at which flexing resistance was tenfold that of room temperature (T by the ASTM Procedures D746 -55T and D1053-54T, respectively. The values were 44 to --48 F. and 43 F., respectively. V i

Further samples were tested for solvent resistance against'a variety of solvents. These tests were performed by ASTM Procedure D47154T at roomtemperature unless indicated otherwise:

- Solvent: Volume percentswell Benzene 201.7

Acetone 130 Ethyl acetate 151.5

' Ethanol v 1 i 3 70:30 isooctane-toluene 19.1

Water at 212 F. 251.2

70:30 isooctane-toluene at 180 F. 70

The other polymers of the invention described in Ex ample 2 when substituted for polythiapentylacrylate in the compounding formula-setiforth above gave rubbe of comparable properties. 7 7

EXAMPLE '4' a r A mixtureof 95 parts of 3-thiapentyl acrylate, 5 parts f hours. The bluish latex which formed was coagulated wherein R is a divalent alkylene hydrocarbon group and.

R is an alkyl group,the sum of the carbon atoms in R A copolymer of a compound of the formula: V a I R-SR'OCCH=CH2 wherein R is a' divalent alkylene'hydrocarbon group and R is an alkyl group, the sum of the carbon atoms in R and R being from 3 to 7, and an equimolar .or smaller amount of a monoethylenically unsaturated vinyl compound. J

8. As an articleof manufacture, a vulcanized composition containing a polymer of a compound of- .the

formula:

' wherein R' 'is a divalent alkylene hydrocarbon. group of acrylic acid, 270 parts'of 'water,5 parts of the sodium salt of alkyl aryl polyether sulfonate, 1 p'art'of potassium persulfate and 0.5 part of so'dium'bisulfite was placed in a suitable vessel, the air flushed outwith "nitrogen'and the whole then heated at C. with agitation for 4 and R is an alkyl group, the sum of the carbon atoms in R and R being from 3 to 7, I said composition having 1 been vulcanized'with sulfur. V

a References Cited in the file of this patent Reppea, Ann. 582, 1-37 (1953). Abstracted in CA. 48, 11306, 7 (1954). I Copy in Library. 

6. A POLYMER OF A COMPOUND OF THE FORMULA: 